she is wondering if she did anything to mess up the relationship. and if she did these different things, what would have happened and if it would change anything that happened over the phone when he told her that they were wrong all along. in the beginning he told her all these stories about them, and she's remembering what happened and looking at the heart with their names in it that he carved in the wall. later in the song she realizes that she's better off without him and that if he didn't talk to her than she could get over him much sooner.
she is wondering if she did anything to mess up the relationship. and if she did these different things, what would have happened and if it would change anything that happened over the phone when he told her that they were wrong all along. in the beginning he told her all these stories about them, and she's remembering what happened and looking at the heart with their names in it that he carved in the wall. later in the song she realizes that she's better off without him and that if he didn't talk to her than she could get over him much sooner.